SMD (Surface Mounting Device) type semiconductor light emitting devices have a wide field of applications since such devices can be surface mounted to a printed circuit board.
With the application field being broadened, the semiconductor light emitting device may be used in a wide range ambient temperature. For example, in the automotive use, the semiconductor light emitting device may be required to be operable in a range of −40–+80 degree Centigrade.
On the other hand, a LED chip, a mold resin, a sealing resin and a metal lead frame have a different heat expansion coefficient and a different Young's modulus. In case an ambient temperature of the semiconductor light emitting device is raised and lowered, the sealing resin is expanded and compressed. So the optical characteristic of the semiconductor light emitting device may be worsened, or damage, such as peeling of the sealing resin from another constituent element and/or cracks in the LED chip, may occur in the semiconductor light emitting device.